Animal Field Guide

American White Pelican

Pelecanus erythrorhynchos
(Pelecanidae)

Montana Species of Concern
Global Rank: G3
State Rank: S3B

Agency Status
USFWS:
USFS: none
BLM: none

The American White Pelican is a large, white bird (length: 127 to 165 cm; weight: most birds 5.0 to 9.0 kg; wingspan: 2.4 to 2.9 m) with black primaries and outer secondaries, an enormous bill with distensible gular pouch, and totipalmate webbed feet. It is often seen in flocks, and when in flight it flies with the head withdrawn. In the early breeding season the bill and legs are bright orange, the head has white plumes, and there is a laterally flattened horn on the upper mandible. Later the leg color fades, the head darkens, and the plumes and horn are lost (Evans and Knopf 1993).

The American White Pelican is unlike other North American birds, except the Brown Pelican (Pelecanus occidentalis), which does not occur inland, and is smaller with generally darker body plumage, and often forages by plunge-diving, whereas the American White Pelican does not (Evans and Knopf 1993). The Snow Goose (Chen caerulescens) and Whooping Crane (Grus americana) display contrasting black primaries and a white body when in flight, similar to the American White Pelican, but are quite different otherwise in appearance and behavior. Snow geese are much smaller than pelicans and fly with their neck extended. Whooping Cranes are often confused with pelicans but are easily distinguished because they fly with their legs and neck extended.

American White Pelicans in Montana are long-distance migrants. Winter recoveries have been made in southern California, and south along the Pacific coast of Mexico and Central America to southern Honduras; along the Gulf coast in the United States there are recoveries from southern Florida to Texas, and south in Mexico to Vera Cruz. There are also scattered winter records from several localities in interior North America (Hendricks and Johnson 2002, E. Madden and M. Restani personal communication).

All colonies have some members that migrate both east and west of the Continental Divide, although the majority of the two western colonies in Montana (Arod Lakes and Canyon Ferry) migrate west across the Continental Divide to southern California and south into Mexico and Central America, whereas the majority of the two eastern colonies in Montana (Bowdoin and Medicine Lake) migrate south and east to the Gulf of Mexico coast and into eastern Mexico. Recoveries or resightings indicate many birds return in spring to their natal colonies to attempt breeding, but there are also a few cases of birds banded at their natal colony returning later to a different Montana colony (Hendricks and Johnson 2002, E. Madden and M. Restani personal communication).

Habitat use in Montana appears similar to other areas within the breeding range. American White Pelicans occur on a variety of aquatic and wetland habitats, including rivers, lakes, reservoirs (both large and small), estuaries, bays, marshes, and sometimes in inshore marine habitats. These habitats are used variously for nesting, loafing, and feeding. They rest on islands and peninsulas, as well as exposed rocks in rivers. Nesting colonies usually are situated on islands or peninsulas in brackish or freshwater lakes, where they are isolated from mammalian predators. Nests are built on the ground in slight depressions or on mounds of earth and debris, usually on low, flat, or gently sloping terrain. They may use dredge spoil or natural islands. Usually nests are built in an open area, but often near vegetation, driftwood, or large rocks (Spendelow and Patton 1988). There is increasing concentration and feeding at catfish aquaculture operations during the non-breeding season (King and Grewe 2001).

Montana breeding colonies are located in the eastern prairie regions on islands or peninsulas of low topographic relief at lakes and reservoirs. Cover at some colonies is minimal, with nests mostly or completely exposed, but nests are often under extensive stands of chokecherry (Prunus virginiana) in the main sub-colony at Medicine Lake (E. Madden and M. Restani personal communication). Feeding occurs near the colony as well as at remote locations (> 100 km) away from the colony in reservoirs, lakes, and along rivers.

Diet at Montana colonies has not been quantified or studied, but observations of prey remains at the Medicine Lake colony include carp (Cyprinus carpio), fathead minnow (Pimephales promelas), suckers (Catostomus spp.), northern pike (Esox lucius), goldeye (Hiodon alosoides), sturgeon (Scaphirhynchus spp.), and adult and larval tiger salamanders (Ambystoma tigrinum) (E. Madden and M. Restani personal communication).

Food observed being consumed at the Canyon Ferry and Arod colonies was primarily non-game fish including suckers, carp, and bullheads.

Distances traveled by adults from nesting colonies to foraging areas can be as much as 100-300 km (Low et al. 1950, Marshall and Giles 1953, Lingle and Sloan 1980, also see Johnsgard 1993). When foraging in mixed-species flocks, especially with Double-crested Cormorants, stealing prey from neighbors (kleptoparasitism) is common. Breeding adults are estimated to eat about 20-40% of their body mass in prey (1.8 kg) per day (Evans and Knopf 1993).

Breeding colony islands in Montana are shared with Double-crested Cormorants and California Gulls. In July, adults appear to go out to feed about dawn, and return in mid-late morning to feed the nestlings.

Generally, this species is very gregarious, often found in flocks or large concentrations throughout the year. Colonies may be quite large, averaging about 1000+ pairs across the global range. In recent years, the size of Montana colonies has been 500-4000 pairs and is increasing (Hendricks and Johnson 2002, E. Madden and M. Restani personal communication). Nesting islands often are shared by other colonial-nesting species, including Double-crested Cormorant, Great Blue Heron, Black-crowned Night-heron, Common Tern, California Gull, and Ring-billed Gull at Montana colonies (E. Madden and M. Restani personal communication). Severe weather, especially hailstorms, can sometimes cause significant mortality among adults and young. Predators at breeding colonies include Common Raven, several large gull species, coyote, and red fox on eggs and young; Great Horned Owl and Bald Eagle take young pelicans (Evans and Knopf 1993).

American White Pelicans arrive at Montana colonies in April, egg-laying and incubation occur during late April through May, young are born in late May and June, and juveniles remain in the colonies until mid-August (P. Hendricks personal observation, E. Madden and M. Restani personal communication). At Medicine Lake, the mean number of young produced per nesting pair since 1990 is 0.51. The oldest bird recovered from a Montana colony was 20 years of age.

Egg-laying most often occurs in April and May throughout the global range, May-July in Texas, and late April-June (mainly before June) in Utah. In Canada, nesting begins in May or June; hatching in the first nests sometimes precedes initiation of the last clutches. The earliest migrants appear at colonies up to 3 weeks before pairing. The period from courtship flights to the onset of egg-laying is about a week. In Manitoba, flocks first flew over colony sites 34-38 days before hatching. Clutch size is commonly 2, but rarely more than one young is fledged per nest. Incubation averages 31-32 days. Both adults incubate eggs and tend the young. Young leave the nest in about 17-28 days while still flightless, and form groups with other young within the colony. In most colonies, juvenile departure begins in late August, when young are about 10-11 weeks of age and 1 week after their first flights (Evans and Knopf 1993).

Mortality of eggs and chicks generally is high, and they generally do not renest following loss of the first clutch. Pelicans reach sexual maturity usually at 3 years of age, and may live 25 years or more (Evans and Knopf 1993).

The four Montana breeding colonies fall into two groupings, based on flyway affiliation. Medicine Lake and Bowdoin are mostly connected to the Central Flyway, with the majority of birds flying south and east to the Gulf of Mexico coast and southern Midwest. Birds at Arod Lakes and Canyon Ferry largely cross the Continental Divide and fly west and south to southern Idaho, California, and western Mexico. While each of the Montana breeding colonies is protected to some degree from predators, human disturbance, and water level fluctuations (each occurs on federal refuges or state management areas), they are vulnerable in winter to shooting and disease. These two factors accounted for 21-47% of band recoveries for the Arod Lakes, Bowdoin, and Canyon Ferry colonies (Hendricks and Johnson 2002). Botulism also leads to the death of several hundred adults and young at the Medicine Lake colony during outbreak years (E. Madden and M. Restani personal communication), and severe weather during the breeding season can contribute to significant mortality at colonies, especially if breeding adults are killed. Conservation of American White Pelicans requires coordinated management at widely separated breeding and wintering sites, as colonies are linked regionally to other breeding colonies through dispersal. Probably the most significant factor in protecting breeding colonies in Montana is maintaining water at appropriate levels to prevent mammalian predator access or flooding of nesting areas. Montana pelicans experienced significant declines in the 1960's and 1970's due to water level fluctuations at their breeding colonies (Sloan 1982). Non-breeding season threats from disease and shooting could also be significant at times, although their impact on colony dynamics is not clear (Hendricks and Johnson 2002). A concurrent color-marking program at each of the Montana colonies, with routine pre- and post-breeding surveys for marked birds, could clarify the isolation of the two colony groupings, the degree of dispersal among the individual colonies within each grouping, and better document colony dispersal during the non-breeding season. The results of this and further studies would help in developing regional management plans that 1) identify current and impending threats to breeding and wintering populations linked through dispersal, 2) provide for coordinated responses to those threats, and 3) support the maintenance of viable populations throughout their global range.